Self-leveling u-gauge



Oct; 13, 193i.

- G. R. STEERE SELF LEVELING 'U-GAUGE- .Filed Au 27, 1927 INVENTOR @anpe Eem ATTORNEY Patented Oct. 13, 1931 UNITED STATES PATENT OFFICE.

' STEERE, OF OWOSSO, MICHIGAN, ASSIGNOR T SEMET-SOLVAY ENGINEER- I NG CORPORATION, OF- NEW YORK, N. Y., A. CORPORATION OF NEW YORK SELF-LEVELING U-GAUGE Application filed August 27, 1927. Serial No. 215,911.

1 each arm of the U and then combine these readings and obtain therefrom the differential pressure corresponding to these levels. This of course, involves considerable time and trouble and due to thenecessity for taking number of readings and calculating the pressure therefrom, there is a greater possibility of introducing error in the results than with a gauge wherein the differential pressure is readdirectly from the scale. Al-

' though there is shown and described herein as an embodiment of my invention a pressure gauge, it will be understood that the invention is not limited to a pressure gauge but may be used to indicate volumes in coni nection with a Venturi meter or the like.

An object of my invention is to provide a gauge "that is simple in construction and efficient in operation. A further object is to provide a self-leveling gauge, that is, a gauge 35. provided with means to restore the pressure liquid which has been forced from the gauge tube by an abnormal pressure to its proper level in said tube without the' formation of air or gas bubbles in the indicating pressure liquid. Another object is to provide a selfleveling gauge of the U-type wherein differential pressures can be read directly from a scale.

7 According tofmy invention there is pro- 'vided apressure indicating device comprising a gauge tube of small capacity, an outer tube of substantial capacity disposed in 'parallel relation to the gauge tube and of greater length, than this tube, an innertube within the louter tube connected at its lower end to the gauge tube and provided with an extension below said connection vented to the lower portion of the outer tube, the inner tube having its upper portion vented to said outer tube so that the liquid emerging from the upper portion is directed towards the side into the bottom of the outer tube, a pipe connected to a source of pressure and to the top of the gauge tube, and a second pipe connected to a source of lower pressure and to the top of the outer tube.

The invention accordingly comprises, a gauge tube, connected to a source of pressure, arranged to contain pr ssure indicating liquid and in communication with a second tube not concentrically positioned with respect to the first mentioned tube, the second tube being in turn connected to a source of lower pressure, and a container for the second tube, the latter tube having means arranged to permit the discharge of liquid into the container when an abnormal pressure is applied to the gauge tube and which permits the return of the liquid into the gauge tube upon a sufficient decrease of pressure therein.

-Other objects and advantages will appear from the following detailed description taken in connection with the accompanying drawings in which Fig. 1 is a side elevation partly broken away and partly in section, of a pressure indicating device illustrating a preferred embodiment of the invention, and showing the 'level of the liquid in the gauge when both the gauge tube and the outer tube are subjected to equal pressures; Fig. 2 is a fragmentary front elevation corresponding to Fig. 1; Fig. 3 is a section partly in elevation on the line 33of Fig. 1; and Fig. 4 is an enlarged longitudinal section of a detail on the line 44 of Fig. 2.

In the preferred embodiment of the invention illustrated on the drawings, 1 indicates a gauge tube of glass or other transparent material mounted in a frame 2 comprising a rear wall 3 provided with suitable graduation indicating pressure in the desired units and side walls 4, 4. Extending through the recess 5 in the wall 3 is a top fitting 6 which has passages or channels 7, 8

disposed at right angles to each other, and

3 .-and the gauge tube 1 is securely confined in the'recesses 9 and 12 of thesefittings by collars 13 surrounding the tube '1 and threadedly engaging nipples, 14 preferably pressure source connected at 19 and that at formed integral with the fittings 6, 11.

Threaded plug "15 provides a {closure for i the gauge'tube 1 and the passageor channel '7 in the top fitting. If it is desired to increase the amount of pressure indicating liquid in the gauge tube, plug 15gis removed and liquid poured through channel 7 into. the gauge tube. singularly plug 16 provides a ('ilosure for the gauge tube 1- and the channel in the bottom fittingll'and by removing this plug liquid can be drained from the gauge tube Apip'e17 hasthe'end 18 screw threaded into countersunk threaded recess 10in the top 'fitting"6 andc has its other end connected through elbow or other joint to a pipe '17 which extends above'the upper end'of the gauge tube and connected througha suitable 7 joint tov pipe 19; i rcommunica'ti'on' with .a source"of'pressure;higher than that in the ,outertubeg V I A, pipe 20 has one end threaded into the countersunk recess in fitting 11 and is con *fn ecte'd at theother end through asuitable fittingand stuffing b'oX 21 to Tfitting 22 whichisconnected at 23"to an innertube 24 Y "or substantially the ame length as the gauge tube jlj Atthe upper end the inner tube 24 hasfthreaded thereon a four-way fitting Q5 Vented M26, 27 and connected at 28 to a pipe QQQWhi'ch in turn is c'onnectedto the T-fitting ior otherindicating liquid is poured'through I channel? 'into gai'lge tube 1 111"'sufic1ent quart 3U vented at "31; "31. The T-fitting 22 has connected at 32 an extension pipe 33 disposed below the junction asshofwn; in Flg. '15

point of pipes 20 and 24 1 Tube 241isfposition'ed within a container "or outertube 34 sothat the extension 33' is Iv'ented to t h'ebottom ofthe outer tube, and 'four-way fitting and the T-fitting are disposed and vented to the top of tube 34.

Outer tube 34 is provided with a head having threadedtherein a pipe 36 which is connected through elbow or other oint to pipe in communicationwith the source of lower pressure. The bottom of outer tube 34 has fastened thereon thel'head 33having threaded therein the valve39 by means of which the pressure indicating liquid can be drained from the outer'tube and thus fromthe inner tube and the gauge tube 1."

clamp 401s bolted or otherwise secured at; 4lto the frame Qan'd also to outerftube 34. thus ,malvnt'alm'ng the assembly 1nipos1- .tion. 7,.

flni'p'reparing the apparatus for use? water into the outer tube 34'.-

tities so that flowing through the connection 20,it fills the inner and outertubes 24, 34 and the gauge tube lto the level 42. If the apparatus is to be used as a differential gauge, the pipevl9 is then connected to a source of high pressure, such as air, and pipe 37 is connectedtoa sourceof low pressure. The difference in pressure existing between the high 3g canbe read directly on-the gauge tube-1-.- it may happen that a sudden or abnormal increaseof pressure in 19 will entirely displace allthe water in the gauge tube 1 as well as .in the inner tube 24 and'thatair will then'rush through the. device and out through head-'35 and pipe 36 intothe tube pass into the gauge tube,,and air will be. ex-

cluded for the reason that the only Way in which the air can rush into tubelis downwardly through theinner tube 24'thro'ugh the bottomof the gauge tube 1. But' the' air can- ,not 'follow,- this. passage because it is blocked the gauge tube.- This sealing occurs-immediatelyupon1any lowering of the pressure sufiicient to permit a returnof liquid into; the gauge tube. The sealing ofthe exit through .theifitting 20 is rapidlyeeffected and" maintained, because the water in extension 33 is unde-r the pressure of the water head in the outer tube plusthe pressure of any air above 'thiswater. .-This combined water and air pressure is of course greater than the pressure of theair attempting to move downwardly through tube 24 into the fitting 20.

In practice the back rush of liquid has sometimes been found so great that it rush-es through the gauge tube, 1, pipe. 17 and'into the pressure source when the pipe 17 is directly connected to thehigh pressure side contaminating the pressure source and causing a loss of some liquid thereby impairing T fitting '22 and-through pipe 20 into the the operationof the gauge. To avoid this 7 pipelVeXtending at right angles to pipe 17 a substantial distance'abovethe upper edge ofj-theg'auge tube is provided and acts as a -check{or-obstruction fQIiitllB liquid prevent-.- the lossofliquid through overflow into the pressure source by. checking the forward flow of the liquid and causing it to return to the gauge vtube. t Y

To use thegauge-as adifi'erential pressure i-ndicatin g device to indicate pressures: above atmospheric pipe ll) 1s connected-to the pressure source as hereinbefore described and a 7 V v:

simplyf "vented to the atmosphere. The device may also; be used to indicate pressuresbelow atmospheric by connecting pipe the outer tube 34 for varying differential pressures may be disregarded for reliable working results. In the conventional type U-gauge it is necessary to take readings of the liquid level in each arm of the U and then combine these readings to obtain the differential pressure existing in the gauge. Both arms of the U being of substantially identical diameter and capacity, the liquid level is forced down in one arm substantially the same amount that it is raised in the other and readings of both are'essential to determine the differential pressure. In my gauge however the capacity of tube 34 is comparatively large as compared with that of gauge tube 1 so that upon the existence of a differential pressure in tubes 1 and 34, the rise in liquid level in outer tube 34 is so small that it may be regarded for reliable working results as a negligible factor on the pressure readings.

In fact for readings corresponding to liquid levels in the upper part of gauge tube 1,

. there is no perceptible change of liquid level In view thereof the reada in outer tube 34. n ings corresponding to the liquid levels of outer tube 34 may be disregarded and the reading of the liquid level in the gauge tube 1 may be regarded for reliable working results as a proper indication of the differential pressure existing in pipes 37, 19.

It will be understood that While a specific embodiment of the invention has been shown and described, various changes in the details thereof may be made by those skilled in. the

art and the. invention is not to be limited to the structure disclosed, but only by the scope of the appended claims.

What is claimed is:

1. A pressure indicating device comprising a gauge tube arranged to contain pressure indicating liquid, a tube connected to said gauge-tube, a third tube connected to said gauge-tube and having one end communicating with said second tube at a point below the connection between said gauge-tube and said third tube and having the other end vented to said second tube at a point above the normal level of pressure liquid in said second tube.

2. A U-gauge pressure'indieating device comprising a gauge-tube forming one arm of theU arranged to contain a pressure indieating liquid and connected to a source of pressure, an outer tube in communication with a source of lower pressure, and a tube within said outer tube connected to said gauge-tube to form the other arm of said U-gauge, said inner tube being provided with; openings arranged to permit the discharge of liquid into the outer tube when an abnormal pres sure is applied to said gauge-tube and per-' mitting the return of the liquid into the gauge-tube upon a decrease of pressure therein, thereby preventing the formation of bubblesin the gauge-tube. l v

" 3. A pressure indicating device comprising a'gauge tube arranged to contain a pressure indicating liquid and connected to a source of pressure, an outer tube in cominunicati on with a source of lower pressure, a

tube within said outer tube and connected tosaid-gauge-tube, said inner tube having a portion extending below said connection to the gauge-tube, the end of said inner tube extending below said connection to the gaugetube being vented to said outer tube, said extending portion being arranged to permit the discharge of the liquid into the outer tube -when an abnornialpressure is applied to said gaugatube and permitting the return of the liquid into the gauge tube upon' a decrease of pressure in said gauge-tube sufiicient to permit tlie return of the liquid.

4. A pressure indicating device-comprising a gauge tube arranged to contain apressure indicating liquid and connected to a source of pressure, an outer tube in communic'ation with. a source'oflowerpressure and a tube within said outer tubeysaid inner tube having its l'ower portion extending to sub- 'stantially the bottom of the outer tube, being connected intermediate its ends with said gauge tube and being vented at both the top and bottom to said outer tube, whereby'an abnormal prcssure in the gauge-tube causes a discharge of the pressure indicating liquid into the outer tube and a decrease of said abnormal pressure causes a return of the liquid into the gauge-tube through said lower extendingportionof the inner tube thereby preventing the format-ion of bubbles in said gauge-tube.

5. A differential pressure gauge of the U- type, comprising a gauge-tube, forming one arm of the U-gauge, an outer tube of greater length than said gauge-tube and an inner tube within said outer tube connected to said gauge-tube vented to said outer tube and forming the other arm of said ,U-gauge, said connection between the inner tube and said gauge-tube occurring intermediate the ends of said inner tube. 1 I

G. A differential pressure gauge of the U- type, comprising a gauge-tube, forming one arm of the U-gauge, a second tube of greater :length than said gauge-tube and of sub s'tantial 'capacityias comparedywithsaid gauge tube and ;connected to, said gauge tube, and a third tube connectedv to said agau'getube, said connection between the third tube and said gauge-tube occurring interniediate the ends of said third tube, one

end. of said" third tube being vented to said 7 second itube,"abovethe normal level of liquid therein, and the other end of said third tube being. vented to substantially the base ofsaid second tube. 1:

975A diifere'ntial pressure gauge comprising a gauge-tube of small diameter, an

outer tube of substantial diameter, and of greater lengththan saidgauge-tube, an inner tube Withinsaidouter tube connected to said gauge-tube and extension tube connected tozthe. junction point of, the gauge-tube and inner tubeand ventedto the bottom of said 1 tube; in communication With the junction outer tube.

: In a differential pressure gauge, a gauge-tube in communication with a source of pressure, an outer tube of greater length than said gauge-tube in'communic-ation with a source of lower-pressure, atube ithin said outer-tube connected at the bottom to the gauge tube' and having its upper portion top of said-gauge-tube, and a second pipe c011 nected to a source of lower'pressureand to the top-of said outertube. 1 r

In witness whereof, Ihave hereuntoset my hand;

. EOR RISTE'E EQ V vented to the outer tube and an extension point of said innerwt'ube, and said gauge-tube V r andei'cten'ding to substantially-the bottom of said outer tubel a 1 e v A'L'PTBSSHIG indicating 'dQVICG COIHPIIS- inga gauge-'tubefa frame Within which said "tube 'niounted;;t:he rearvm'1l 0f said frame having ,graduations to provide-a scale for. said tube, an outer tube of substantial capacas compared: with i said Igaug'e-rtube disposed: in paraflel relation to said gauge-tube and of 'greaterlength than said'fgauge-tube,

at lower end .to the gauge-tuberand 'pro- "vided with an eiztension below said connec- 'ti-.on, said extension being. vented to the lower ia'n iniier tube Within the. outer tube-connected 7 portion iofthe outer tube,- Fsaid inner tube batting its upper portion vented to said outer tube so the 'Iiquideinerging from said 1 upper portion is directed 'towa rdsthesides to the bottom ofzsaid outer tube, agpipe conneeteditoa source of pressure and to the top of said gauge-tube, a second pipe connected to a source of lower pressure and to the'top of vswidou'ter tube andia' clampfo-r. fastening "said f-rameto saidoutertube. 10. A pressure indicatm'g device comprlsiiig-a gillG-tllbfl, a frame, top; and bottom fittings for securing :said gauge-tube Within said frame, an outer tube ot-substantial capacityas compared with" said gauge-tube, I disposed in p-arallelcrelation tov sazid gauge tube and of greater length "than said gaugetube; valve in the lower portion of said outer tube, an inn'er' tube .within the outer tube 'coninedte'd at its lower end-to the -gauge- 7 j :tube andprovlded with an'extension{below 

